Is personification a rhetorical device?
Yes it is. See explanation.
Yes. A personification is a device which gives human abilities to a non human being or an abstract idea.
"And Death spoke to them. He was angry that he had been cheated(...) "
In this fragment Death is given human ability to speak. The reaction of Harry Potter indicates that he was shocked.
*'Sorry,' interjected Harry, 'but Death spoke to them?' *
Given example comes from 'Harry Potter and the Deathly Hallows' by J. K. Rowling Chapter 21, page 330.